1. Field of the Invention
The present invention relates to thermoplastic polymers modified with certain fluorocarbon additives.
2. Description of the Prior Art
It has recently been proposed to modify thermoplastic polymers by incorporating therein various oils, gums, etc.
U.S. Pat. No. 3,485,787 discloses that certain block copolymers may be extended by incorporating mineral oil therein. U.S. Pat. No. 3,830,767 teaches that bleeding of the extending oil from the block copolymer may be prevented by incorporating a petroleum hydrocarbon wax therein.
U.S. Pat. No. 4,123,409 relates to block copolymers having thermoplastic terminal blocks and an elastomeric intermediate block. The patent discloses blending with the copolymer a high molecular weight oil which is compatible with the elastomeric block portion of the copolymer. Where the elastomeric portion is a hydrocarbon, the oil employed is a mineral oil. Where the elastomeric block is a polysiloxane, a silicone oil is blended therewith.
U.S. Pat. No. 3,034,509 discloses the addition of silicone oil to polyethylene for use as surgical tubing.
U.S. Pat. No. 4,386,179 discloses the dispersion of a polysiloxane throughout an elastomeric thermoplastic hydrocarbon block copolymer.
Japanese Patent No. 60-104161 describes an anti-friction composite material comprising a resin and more than 1%, by weight, of a fluorocarbon oil which have been injection molded together in a manner such that the oil exudes onto the molded surfaces of the resin due to poor compatibility of the oil with the resin and differences in viscosity between the resin and oil to produce an anti-friction surface.
European Patent No. 222,201 mentions perfluorosilicone oils for use in vulcanizable non-thermoplastic rubber compositions. Their use is said, however, to result in difficulties with respect to mixing, a reduction in the vulcanization rate and a worsening of the compression set value and thermal stability.
There is continuous research leading to the development of novel polymeric materials whose properties are tailored by incorporating therein various additives.
In application Ser. No. 07/446,675, filed Dec. 6, 1989, now aBN there is described a composition of matter having advantageous properties formed by melt-blending a thermoplastic polymer and from about 0.01% to less than 1%, by weight, of a perfluorocarbon additive, the properties of the polymer and the additive being such that, in the solid product obtained, the concentration of the perfluorocarbon additive is a gradient through a cross-section of the solid from a lower value in the interior to a higher value at the surfaces thereof.
It is an object of the present invention to provide novel thermoplastic polymer compositions having unique properties and which find utility in a wide variety of applications.
It is another object of the invention to provide a novel method for preparing thermoplastic polymer compositions having properties and characteristics heretofore unattainable.